Windscreen wiper blades are fitted detachably on the extremity of a wiper arm and must be replaced periodically in order to ensure good wiping, which is a safety prerequisite. Thus wiper arms are equipped at their extremities with a hook attachment element which co-operates with a complementary element of the wiper blade to permit such replacement. However numerous types of arms exist having different hook attachment systems, so that even on vehicles of the same type it is necessary to provide a replacement wiper blade adapted to the type of arm with which the vehicle was originally equipped.